gnu-social/lib/activityutils.php

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<?php
/**
* StatusNet, the distributed open-source microblogging tool
*
* An activity
*
* PHP version 5
*
* LICENCE: This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* @category Feed
* @package StatusNet
* @author Evan Prodromou <evan@status.net>
* @author Zach Copley <zach@status.net>
* @copyright 2010 StatusNet, Inc.
* @license http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPLv3
* @link http://status.net/
*/
if (!defined('STATUSNET')) {
exit(1);
}
/**
* Utilities for turning DOMish things into Activityish things
*
* Some common functions that I didn't have the bandwidth to try to factor
* into some kind of reasonable superclass, so just dumped here. Might
* be useful to have an ActivityObject parent class or something.
*
* @category OStatus
* @package StatusNet
* @author Evan Prodromou <evan@status.net>
* @copyright 2010 StatusNet, Inc.
* @license http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPLv3
* @link http://status.net/
*/
class ActivityUtils
{
const ATOM = 'http://www.w3.org/2005/Atom';
const LINK = 'link';
const REL = 'rel';
const TYPE = 'type';
const HREF = 'href';
const CONTENT = 'content';
const SRC = 'src';
/**
* Get the permalink for an Activity object
*
* @param DOMElement $element A DOM element
*
* @return string related link, if any
*/
static function getPermalink($element)
{
return self::getLink($element, 'alternate', 'text/html');
}
/**
* Get the permalink for an Activity object
*
* @param DOMElement $element A DOM element
*
* @return string related link, if any
*/
static function getLink(DOMNode $element, $rel, $type=null)
{
$els = $element->childNodes;
foreach ($els as $link) {
if (!($link instanceof DOMElement)) {
continue;
}
if ($link->localName == self::LINK && $link->namespaceURI == self::ATOM) {
$linkRel = $link->getAttribute(self::REL);
$linkType = $link->getAttribute(self::TYPE);
if ($linkRel == $rel &&
(is_null($type) || $linkType == $type)) {
return $link->getAttribute(self::HREF);
}
}
}
return null;
}
static function getLinks(DOMNode $element, $rel, $type=null)
{
$els = $element->childNodes;
$out = array();
foreach ($els as $link) {
if ($link->localName == self::LINK && $link->namespaceURI == self::ATOM) {
$linkRel = $link->getAttribute(self::REL);
$linkType = $link->getAttribute(self::TYPE);
if ($linkRel == $rel &&
(is_null($type) || $linkType == $type)) {
$out[] = $link;
}
}
}
return $out;
}
/**
* Gets the first child element with the given tag
*
* @param DOMElement $element element to pick at
* @param string $tag tag to look for
* @param string $namespace Namespace to look under
*
* @return DOMElement found element or null
*/
static function child(DOMNode $element, $tag, $namespace=self::ATOM)
{
$els = $element->childNodes;
if (empty($els) || $els->length == 0) {
return null;
} else {
for ($i = 0; $i < $els->length; $i++) {
$el = $els->item($i);
if ($el->localName == $tag && $el->namespaceURI == $namespace) {
return $el;
}
}
}
}
/**
* Grab the text content of a DOM element child of the current element
*
* @param DOMElement $element Element whose children we examine
* @param string $tag Tag to look up
* @param string $namespace Namespace to use, defaults to Atom
*
* @return string content of the child
*/
static function childContent(DOMNode $element, $tag, $namespace=self::ATOM)
{
$el = self::child($element, $tag, $namespace);
if (empty($el)) {
return null;
} else {
return $el->textContent;
}
}
static function childHtmlContent(DOMNode $element, $tag, $namespace=self::ATOM)
{
$el = self::child($element, $tag, $namespace);
if (empty($el)) {
return null;
} else {
return self::textConstruct($el);
}
}
/**
* Get the content of an atom:entry-like object
*
* @param DOMElement $element The element to examine.
*
* @return string unencoded HTML content of the element, like "This -&lt; is <b>HTML</b>."
*
* @todo handle remote content
* @todo handle embedded XML mime types
* @todo handle base64-encoded non-XML and non-text mime types
*/
static function getContent($element)
{
return self::childHtmlContent($element, self::CONTENT, self::ATOM);
}
static function textConstruct($el)
{
$src = $el->getAttribute(self::SRC);
if (!empty($src)) {
throw new ClientException(_("Can't handle remote content yet."));
}
$type = $el->getAttribute(self::TYPE);
// slavishly following http://atompub.org/rfc4287.html#rfc.section.4.1.3.3
if (empty($type) || $type == 'text') {
// We have plaintext saved as the XML text content.
// Since we want HTML, we need to escape any special chars.
return htmlspecialchars($el->textContent);
} else if ($type == 'html') {
// We have HTML saved as the XML text content.
// No additional processing required once we've got it.
$text = $el->textContent;
return $text;
} else if ($type == 'xhtml') {
// Per spec, the <content type="xhtml"> contains a single
// HTML <div> with XHTML namespace on it as a child node.
// We need to pull all of that <div>'s child nodes and
// serialize them back to an (X)HTML source fragment.
$divEl = ActivityUtils::child($el, 'div', 'http://www.w3.org/1999/xhtml');
if (empty($divEl)) {
return null;
}
$doc = $divEl->ownerDocument;
$text = '';
$children = $divEl->childNodes;
for ($i = 0; $i < $children->length; $i++) {
$child = $children->item($i);
$text .= $doc->saveXML($child);
}
return trim($text);
} else if (in_array($type, array('text/xml', 'application/xml')) ||
preg_match('#(+|/)xml$#', $type)) {
throw new ClientException(_("Can't handle embedded XML content yet."));
} else if (strncasecmp($type, 'text/', 5)) {
return $el->textContent;
} else {
throw new ClientException(_("Can't handle embedded Base64 content yet."));
}
}
/**
* Is this a valid URI for remote profile/notice identification?
* Does not have to be a resolvable URL.
* @param string $uri
* @return boolean
*/
static function validateUri($uri)
{
if (Validate::uri($uri)) {
return true;
}
// Possibly an upstream bug; tag: URIs aren't validated properly
// unless you explicitly ask for them. All other schemes are accepted
// for basic URI validation without asking.
if (Validate::uri($uri, array('allowed_scheme' => array('tag')))) {
return true;
}
return false;
}
}